1864.] 
451 
ally twice as long as in spongijica, and consequently the sheaths of the 
ovipositor (Fig. I, ss) are also proportionally twice as long, though 
their proportional breadth in both forms is nearly the same. 
9th. With the exception of a single specimen, my 30 $ aciculata 
are i broader and longer than my 5 $ spongijica and my 9 $ inanis, all 
14 of which are remarkably uniform in size, save a single 9 manis 
which is a little smaller than the rest. 
These nine differences are sufficiently remarkable, and but for the 
evidence of dimorphism would undoubtedly be viewed by every ento¬ 
mologist as of specific value. Three other differences stated by Osten 
Sacken I do not find to be strictly correct. 
1st. In both forms the antennae are of a uniform, opaque, dark red¬ 
dish brown, and not “ pitch black” in aciculata and “ brown or reddish 
brown especially towards the tip’’ in spongijica. (^Proc. Ent. Soc. 
Phila. I, pp. 56 and 242.) The two basal joints, however, are blacker 
and a little inclined in some specimens to be polished. 
2nd. In both forms the areolet is, on the average of specimens, 
equally distinct and not “ more distinct” in aciculata. (Ibid. p. 57.) 
Of course, on account of the larger size of the insect, it is absolutely 
but not relatively larger in aciculata. 
3rd. In both forms the antennae 9 are 13-jointed, the last joint 
nearly as long as the two preceding ones put together and with one 
more or less distinct transverse impression slightly behind its middle; 
or, to state the same thing in other terms, the antennae 9 are I4-jointed, 
the two last joints connate and almost confiuent. Osten Sacken errone¬ 
ously says that in spongijica 9 the antennae are 13-jointed, the last 
joint “ with two indistinct transverse sutures foreshadowing the 14th 
and 15th joints of the S ;” and that in aciculata 9 the antennae are 
“ 14-jointed, the last joint being separated from the penultimate one 
by a suture as distinct as that of all the other joints.” (Proc. Ent. Soc. 
Phila. I, p. 246.) In some specimens of aciculata^ and it was probably 
such that Baron Osten Sacken received from me, the connate suture or 
transverse impression of the 13th joint is much more distinct than in 
others, but even in such specimens it disappears when viewed in cer¬ 
tain lights, the other or true sutures remaining visible. In no speci¬ 
mens is it a true or free suture, as I ascertained by examining and re¬ 
examining dozens of specimens both in life and in death. Neither 
